Di-(2-phenoxyethyl)peroxydicarbonate

ABSTRACT

DI-(2-PHENOXYETHYL) PEROXYDICARBONATE AND IMPROVED PROCESSES EMPLOYING SAME AS INITATORS FOR THE POLYMERIZATION OF THE ETHYLENICALLY UNSATURTED MONOMERS (SUCH AS VINYL) CHLORIDE) AND A S CURING CATALYSTS FOR CURING UNSATURATED POLYMER RESIN COMPOSITIONS.

"United' States Patent 01 hoe 3,799,966 Patented Mar. 26, 1974 3,799,966 DI-(Z-PHENOXYETHYL) PEROXYDICARBONATE Jose Sanchez, Grand Island, N.Y., assignor to Pennwalt Corporation, Philadelphia, Pa. No Drawing. Filed Dec. 17, 1971, Ser. No. 209,435 Int. Cl. C07c 73/10; C08f N60 US. Cl. 260-463 1 Claim ABSTRACT OF THE DISCLOSURE Di-(2-phenoxyethyl) peroxydicarbonate and improved processes employing same as initiators for the polymerization of ethylenically unsaturated monomers (such as vinyl chloride) and as curing catalysts for curing unsaturated polyester resin compositions.

BACKGROUND OF THE INVENTION (a) Field of invention This invention relates to novel di-(2-phenoxyethyl) peroxydicarbonate (1),

a peroxydicarbonate of unusually high thermal stability which can be transported and stored nonrefrigerated, and to its use as a free-radical initiator in polymerizations of ethylenically unsaturated monomers and as a curing catalyst for unsaturated polyester resins.

Dialkyl peroxydicarbonates are low temperature freeradical polymerization initiators (and curing agents) which are displacing the well-known dilauroyl peroxide in vinyl chloride polymerizations owing to the superior efliciencies of these initiators. The switch to the lower temperature dialkyl peroxydicarbonates from dilauroyl peroxide was not made without problems, however. Dialkyl peroxydicarbonates such as the commercially available IPP (diisopropyl peroxydicarbonate) have stringent refrigerated storage and shipping requirements which are designed to maintain assay and prevent explosive decompositions upon inadvertent warming. On the other hand, dilauroyl peroxide does not require refrigeration during storage and shipping. Numerous domestic as well as foreign -PVC[poly(vinylchloride)] manufacturers would like to switch from dilauroyl peroxide to the more efiicient dialkyl peroxydicarbonates; however, a number of reasons prevent them from doing so. Some domestic PVC producers are not along the routes used by peroxide producers to supply their customers via refrigerated trucks; hence, refrigerated shipments of dialkyl peroxydicarbonates are not frequent. This means that these producers have to keep large amounts of dialkyl peroxydicarbonates on hand and must receive large shipments of these peroxydicarbonates in order to make it worthwhile (economically) for the peroxide produced to ship to them. Hence, the PVC producers who art not on the refrigerated truck routes must either maintain large and costly refrigerated storage facilities for peroxydicarbonates or they have to use less eflicient but more stable dilauroyl peroxide. Another reason that some domestic PVC producers give for not using peroxydicarbonates is the hazard that results from accidental warming to ambient temperatures. IPP will detonate after warming to room temperature. Many foreign PVC producers or potential PVC producers would like to use the more efficient dialkyl peroxydicarbonates for commercial vinyl chloride polymerizations; however, many of these PVC producers are located in countries which do not have manufacturers of dialkyl peroxydicarbonates or of alkyl chloroformates (precursors to peroxydicarbonates) or of phosgene (used to make alkyl chloroformates). This is especially true of PVC producers or potential PVC producers who are located in some of the developing countries of the world such as India, the countries of Southeast Asia, Africa, and Central and South Americas and the Arab nations. Almost all of the developing countries are in the subtropical to tropical areas of the world; hence, ambient temperatures over F. would not be uncommon. Refrigerated shipment of peroxydicarbonates from producers in the United States or Europe to PVC producers in these developing nations by sea or other carrier would be out of the question owing to the cost of the refrigerated shipment and cost of refrigerated storage to the PVC producer. Hence, there is a need for a dialkyl peroxydicarbonate which can be shipped and stored without refrigeration and one which would survive the highest ambient temperatures which would be encountered without decomposing violently and without losing assay during nonrefrigerated transport and storage. Dialkyl peroxydicarbonates which could be useful would, at times, be subjected to temperatures of 50 C. (122 F.) and possibly even 60 C. F.) for short periods of time. Hence, the desired dialkyl peroxydicarbonate would have to survive under these conditions. One peroxide producer determines whether or not a peroxide can be shipped and stored non-refrigerated by testing its thermal stability at 50 C. for one week. If it does not decompose violently during this test, it can be shipped and stored without need of refrigeration. The peroxide producers prefer that the peroxide tested would survive for at least 24 hours at a higher temperature and/or for a longer period of time at 50 C. since this would result in a greater margin of safety. One thermal stability test which could be run on prospective stable peroxydicarbonates would be a 60 C./l. day thermal stability test. Since dialkyl peroxydicarbonates usually have 10 hour half-lives (in a solvent) at about 40 to 50 C., one would not expect them to survive long at 50 C. and certainly not long at 60 C. In the art, there are many dialkyl peroxydicarbonates which are stable at room temperature (20 C. to 30 C.). However, all of these must be shipped and stored refrigerated owing to the high temperatures encountered during shipping and storage.

(b) Related art Strain [U.S. Pat. No. 2,370,588 and J. Am. Chem. Soc., 72, 1254 (1950)] discloses the preparations of various dialkyl peroxydicarbonates, including commercially available and hazardous peroxydicarbonates such as IPP. Among those listed is dibenzyl peroxydicarbonate (2) bonates such as di-(4-t-butylcyclohexyl) peroxydicarbonate; Netherlands application 6,917,105 discloses di(hexadecyl) peroxydicarbonate; German OLS 2,034,922 discloses di- 3 (cis-3,3,5-trimethylcyclohexyl) peroxydicarbonate; and German OLS 2,034,964 discloses various solid di(bicycloalkyl) peroxydicarbonates such as diisobornyl peroxydicarbonate. As shown below, these compounds are also unstable at temperatures of 35-50 C.

German OLS 1,957,386 claims room temperature stable peroxydicarbonates of general structure (4):

where R is alkyl or halogen, X is oxygen, and R and R are alkyl groups which can be interrupted with oxygen atoms, and discloses di-(3-phenoxypropyl) peroxydicarbonate (5):

I 'l [@owumob OI which is shown below to decompose violently after 8 hours at 50 C.

BRIEF SUMMARY OF THE INVENTION This invention concerns:

(A) Novel di-(Z-phenoxyethyl) peroxydicarbonate, a

usually safe and stable peroxydicarbonate; and (B) Improved processes for l) polymerizing ethylenically unsaturated monomers which are responsive at suitable temperatures to initiating amounts of free radical polymerization initiators, and (2) curing unsaturated polyester resin compositions by heating in the presence of initiating amounts of free radical curing catalysts, the improvement residing in the use of di-(Z-phenoxyethyl) peroxydic-arbonate as said initiator or curing catalyst.

DETAILED DESRIPTION OF INVENTION Dialkyl peroxydicar-bonates normally have 10-hour halflives (in a solvent) at about 40-50 C. and accordingly are not expected to survive long at 50 C. or higher. This is borne out by the fact that dialkyl peroxydicarbonates heretofore disclosed are stable at room temperature but unstable at 50-60 C.

Nevertheless, it has now been discovered that di(2- phenoxyethyl) peroxydicarbonate not only passes the 50 C. test with little or no loss of assay, but also only loses 3% of its assay after 24 hours at 60 C. Thus a peroxydicarbonate has now been found which can be transported and stored under almost any temperature condition without need of refrigeration.

Polymerization In the free radical initated polymerization of ethylenically unsaturated monomers at suitable temperatures, the subject peroxydicarbonate is also found to be highly efficient. In fact, it is found to be more than seven times as efficient as lauroyl peroxide (an industry standard) on a molar basis in the polymerization of vinyl chloride, and more eificient on both molar and weight bases than dibenzyl peroxydicarbonate (currently being promoted as a replacement for lauroyl peroxide), even though di-(2- phenoxyethyl) peroxydicarbonate has a higher molecular weight than dibenzyl peroxydicarbonate.

Suitable monomers include olefins such as ethylene, propylene, styrene, chlorostyrene, vinyltoluene, vinylpyridine, divinylbenzene and alphamethylstyrene; conjugated olefins such as 1,3-butadiene, isoprene and chloroprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl laurate, vinyl benzoate and divinyl carbonate; allyl esters such as allyl acetate, diallyl carbonate, allyl benzoate and diallyl phthalate; unsaturated conjugated nitriles such as acrylonitrile and methacrylonitrile; acrylic acid and methacrylic acid and their esters and amides such as methyl, n-butyl and 2-ethylhexyl acrylates and methacrylates and acrylamide and methacrylamide; maleic anhydride; maleic acid and fumaric acid and their esters; vinyl halo and vinylidene halo compounds such as vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride and vinylidene fluoride; perhalo olefins such as tetrafluoroethylene, hexafluoropropylene and chlorotrifiuoroethylene; vinyl ethers such as methyl vinyl ether and n-butyl vinyl ether; acrolein; and mixtures thereof. A preferred monomer is vinyl chloride.

Temperatures of about 0-150 C. (preferably 35- 75 C.) and peroxide levels of about 0.003-0.300% or more (preferably 0.01-0.20%) by weight, based on the polymerizable monomer, are normally employed in these processes. Conventional solvents can optionally be added to the reaction system.

Curing of polyester resins In curing unsaturated polyester resin compositions-by heating at suitable curing temperatures in the presence of free radical curing catalysts, the use of di-(2-phenoxyethyl) peroxydicarbonate is found to have a greater actlvity (result in faster cures) than dibenzoyl peroxide (a commercially available low temperature curing catalyst).

Unsaturated polyester resins curable by the invention peroxide normally consist of an unsaturated polyester and a polymerizable monomer.

The unsaturated polyester component is normally obtained by the esterification of one or more ethylenically unsaturated dior polycarboxylic acids or their anhydrides, such as maleic acid, fumaric acid, glutaconic acid, itaconic acid, mesaconic acid, citraconic acid, allylmalonic acid, allylsuccinic acid, and others, with saturated or unsaturated polyalcohols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 2,2-dimethyl-l,3- propanediol, 2-buten-1,4-diol, 2-butyn-l,4-diol, glycerol, 2,2,4-trirnethyl-1,3-pentanediol, 2,2,4,4 tetrarnethyl-l,3- cyclobutanediol, l,4-di(hydroxymethyl)cyclohexane, 1,2, S-hexanetriol, pentaerythritol, mannitol and others. Mixtures of such acids and/ or alcohols may also be used. The unsaturated dior polycarboxylic acids may be replaced, at least partly, by saturated, carboxylic acids such as adipic acid, succinic acid, sebacic acid and others, or by aromatic dicarboxylic acids, such as phthalic acid, tetrahydrophthalic acid, and others and their anhydrides such as phthalic anhydride. The acids used as well as the alcohols employed may be substituted by halogen or other substituents, preferably by halogen. Examples of such suitable halogenated acids are, for instance, tetrachlorophthalic acid, 1,4,5,6,7,7-hexachloro-2,3-dicarboxybicyclo (2.2.1)- S-heptene, and others, or their anhydrides.

The other component of the unsaturated polyester resin compositions is an ethylenically unsaturated monomer, preferably ethylenically unsaturated monomers such as styrene, chlorostyrene, vinyltoluene, methyl methacrylate, diallyl phthalate, dibutyl fumarate, acrylonitrile, triallyl cyanurate, a-methylstyrene, divinylbenzene, methyl acrylate, diallyl maleate, ethyl methacrylate, ethyl acrylate and others, which are copolymerizable with said unsaturated polyesters.

A preferred resin composition contains as the polyester component the esterification product of propylene glycol (-a polyalcohol), maleic anhydride (an anhydride of an unsaturated dicarboxylic acid) and phthalic anhydride (an anhydride of an aromatic dicarboxylic acid) and as the monomer component styrene.

Temperatures of from about 20 C. to about 170 C. (preferably 50 C. to C.) and peroxide levels of from about 0.05% to about 5.0% or more (preferably 0.2% to 2.5%) by weight of curable unsaturated polyester resin are normally employed.

5 EXAMPLES The following examples illustrate the subject invention, but are not in limitation thereof.

EXAMPLE I Preparation of di-(2-phenoxyethyl) peroxydicarbonate 2-phenoxyethyl chloroformate was prepared in 98.2% assay and 92.8% corrected yield by reacting 0.35 mole of 2-phenoxyethanol with 0.65 mole of phosgene followed by removal of excess phosgene.

A jacketed reactor equipped with a mechanical stirrer, a thermometer and an addition funnel was charged with 60 g. of water and two drops of polyethoxylated nonylphenol (surfactant) and the resulting solution was cooled to C. To it was added 52.0 g. (0.26 mole) of 20% aqueous sodium hydroxide solution followed by dropwise addition of 8.85 g. (0.13 mole) of H 0 (50%). To this vigorously stirred solution at C. to C. was slowly added a solution of 49.0 g. (0.245 mole) of 2-phenoxyethyl chloroformate (98.2%) in 75 ml. of methylene chloride over a 40 minute period. The reaction mixture was then stirred for 3 hours at 10 C. to C. To the mixture was added 150 ml. of methylene chloride in order to completely dissolve the product. -After separation of the aqueous layer the methylene chloride solution was washed with 40 ml. of 10% aqueous sodium hydroxide solution and then with water to neutral. The resulting solution was dried over anhydrous MgSO and, after separation of the used desiccant, the methylene chloride was removed in vacuo. The solid product which remained was stirred with cold diethyl ether and after filtration 37.2 g. of white solid, M.P. 97100 C., was obtained. The assay of the product according to active oxygen content was 99.5%, hence the corrected yield was 85.2%.

EXAMPLE IIA Thermal stabilities of di-(2phenoxyethyl) peroxydicarbonate and di-(S-phenoxypropyl) peroxydicarbonate Using the method employed in Example I di-(3-phenoxypropyl) peroxydicarbonate was prepared with an assay of 92.7% and in a corrected yield of 92.0%. This material was stirred with cold diethyl ether and the solid was separated by filtration. The product had a melting point of 51-53 C. and had an assay of 98.4% according to active oxygen content.

Thermal stability test at 50 C. and 60 C.

In one test 15 g. samples of di-(2-phenoxyethyl) peroxydicarbonate (99.5% assay) and of di-(3-phenoxypropyl) peroxydicarbonate (98.4% assay) were placed in an oven which was maintained at 50 C. The test was stopped if the peroxide decomposed vigorously, otherwise, it was continued and the assay loss was determined after various time intervals. The results are summarized in Example IIA Table and show that di-(2-phenoxyethyl) peroxydicarbonate is unexpectedly more EXAMPLE IIA TABLE-THERMAL STABILITIES AT 50 C.

Total assay] Peroxydicarbonate Vigorous decomposition loss after Dl-(2-phenoxyethyl) No 1.0%/l week.

Do No 1.0%/2 weeks. Do No 1.0%/4 weeks. Di-(3-phenoxypropyl) Yes 100%[8 hours.

ing vigorously and that it should lose only 1.0% of its assay after 4 weeks at 5 0 C.

The slight difference in the assays is not responsible for the observed greater stability of di-(Z-phenoxyethyl) peroxydicarbonate over di-(3-phenoxypropyl) peroxydicarbonate since the assay of di-(2-phenoxyethyl) peroxydicarbonate, after one week at 50 C., was about the same as that of di-(3-phenoxypropyl) peroxydicarbonate and it did not decompose or lose any further assay during the next three weeks.

In the other test 15 g. of di-(Z-phenoxyethyl) peroxydicarbonate (99% assay) was placed in an oven at 60 C. for 24 hours and the assay was determined. It lost only 3% of its assay. Di-(3-phenoxypropyl) peroxydicarbonate was not tested in this way since its behavior at 50 C./ 8 hours would suggest that it would decompose violently after a short period of time at 60 C.

Hence, these results show that di-(Z-phenoxyethyl) peroxydicarbonate the peroxide of this invention, has thermal stability of about 15 C. higher than that of di-(3- phenoxypropyl) peroxydicarbonate.

EXAMPLE IIB Thermal stabilities of di-(2-phenoxyethyl) peroxydicarbonate (l) and di-(l-phenoxy-Z-propyl) peroxydicarbonate (6) CH; O

Using the process employed in Example I di-(l-phenoxy-2-propyl) peroxydicarbonate was prepared. After one recrystallization of the crude product from diethyl ether the product, a solid, M.P. 71-75 C., was obtained in 51.0% corrected yield. The assay was 98.0%. 4

In the thermal stability tests at 50 C. 15 g. samples of di-(Z-phenoxyethyl) peroxydicarbonate (99.5% assay) and di-(1-phenoxy-2-propyl)peroxydicarbonate (98.0% assay) were placed in an oven which was held at 50 C. Individual tests were stopped if the peroxide decomposed vigorously, hence the assay loss was considered to be 100%. When the peroxide did not decompose vigorously the assay loss was determined after various time intervals. The results are summarized in Example IIB Table and show that di-(2-phenoxyethyl) peroxydicarbonate, the invention peroxide, is unexpectedly more stable than is di- (l-phenoxy-Z-propyl) peroxydicarbonate, a peroxy dicarbonate which is structurally similar to di-(Z-phenoxyethyl) peroxydicarbonate.

EXAMPLE IIB TABLE-THERMAL STABILITIES AT 50 C.

Total assay Vigorous loss,

Peroxydicarbonate decomp. Test duration percent Di-(2phenoxyethyl) No 1 week 1. 0

Do No 2 weeks 1. 0

Do No 4weeks 1.0

D1-(1-phenoxy-2-propy1) Yes Less than 2 days..- 100 EXAMPLE III The thermal stabilities of known solid peroxydicarbonates compared to that of di-(2-phenoxyethyl) peroxydicarbonate phenoxyethyl) peroxydicarbonate, the peroxide of this invention, has much greater thermal stability than any of the known solid peroxydicarbonates. The high thermal stability of di-(Z-phenoxyethyl) peroxydicarbonate means that the pure peroxide can be shipped and stored non- 8 I lymerizations were run at 50 C. for 8 hours in order to determine the amounts of dibenzyl peroxydicarbonate, dilauroyl peroxide and di-(2-phenoxyethyl) peroxydicarbonate, the invention peroxide, required at 90% conversion of vinyl chloride. The following recipe was employed refrigerated and will survive without decomposing or in these polymerizations: losing significant assay for long periods of time at 50 C. (122 F.) and will survive without decomposing violently for short periods of time at 60 C. (140 F.). No known s i i' chloride monomer Parts by peroxydicarbonate has thermal stability as great as di-(2- wager (m i p e lstllled) 130 phenoxyethyl) peroxydlcarbonate. Its high thermal stabil- Methocei 1 (65 HG, 50 CPSJ (1% aqueous lty puts it 111 a class by itself since it can be stored and 801m) 60 transported wlthout need of refrlgeratlon, whereas, the Aerosol M A2 (1% aqueous Soil) 60 others as pure peroxydicarbonates must be refrlgerated. Free radicai initiator variable While the other so-called stable peroxydicarbonates are stable at room temperature, (1) is room temperature lMeth lcenul Ch 1 1C Stable as w as stable at hlghest amblent temper' 2 S0diu in salt i dlli ryl s b lf ciuc nate (American Cyanaatures which may occur during transport and storage mid 00.). (50 C. to 60 C.). Procedure 35H35$5Eifififiltfg" TESTS Pop bottles were employed. Water, aqueous Methocel Percent and aqueous Aerosol MA were added to each bottle and assay the contents were frozen at --20 C. To the bottles were Peroxydicarbonate emp-ld a 10st then added varying amounts of free-radical initiators Dibenzyl 30: O./4weeks 0.0 (Several t e q each initiator) and the required B8 Eg Jig 1-; mount of l qllld vmyl chloride monomer (at 14 Q). 1: g gjjjj Th: blottleis were crown-capped, enclosgd 1ln satiety cages Do 60'; an p ace in a constant temperature ott e 0 merizer i i =i W4 &8 maintained at 50 C. End-over-end tumbling at Z rate of dgg y 23: z f'g g 2g 30 25 revolutions per minute was employed for agitation Dieis-ifisit 1 gjjjj .5 and the polymerizations were allowed to proceed for 8 gf 23: 814 $33?" 3-8 hourst e end of that time the bottles were removed m-e-pheiioiiietiiyoiiiiiIIIII' 30 oi/i weeksiijj 010 frorn the bottle pols/merizer, cooled to 0 C. and vented g g3; 8 42:332 g g of vinyl chloride monomer. Venting of unreacted vinyl 11: C /1 day chloride monomer seldom took more than 15 to 30 min- -p yp l y W hours-m utes; hence, post-polymerization was insignificant. The 1(Degomposedyvithforce), amount of polymer produced was determined gravimet- EXAMPLE 1v iy y difference in eight) and plots of initiator required versus percent conversion were constructed for Safety tests 011 dlbelllyl peroxydicarbonate and each initiator and the amounts of initiators (in grams -p y y peroxydicarbonate and in moles) required at 90% conversion were deter- Owing to the fact that dibenzyl peroxydicarbonate is mmed from the P These 6 a e Shown in Exambeing commercialized as the most thermally stable per- P V Table and w that 'P Y y p yoxydicarbonate up to this time, it and di (2 phenoxy cllcarbonate, the peroxlde of this mvention, is cons derably ethyl) peroxydicarbonate, the peroxide of this invention, 45 more efficfent that dlilauroyl peroxld? and slgnlficallfly were subjected to various safety tests which are well 'f efficlent than 15 dlbenzifl peroxydlcftlrbonate- Hence, known (see I. Van-avandi and L Mageli: safe dl-(2-phenoxyethyl) peroxydicarbonate 1s not only safer Handling of Organic peroxides, L chain Ed 48 and more thermally stable than dibenzyl peroxyd carbo- 5 (1971), which iS incorporated herein by reference) nate, it is more efiiclent 1n vinyl chloride polymerization. The results of these tests are summarized in Example IV 5 Table EXAMPLE v TABLE EXAMPLE IV TABLE-SAFETY TESTS VCl susp. polym. at 50 C./8 hours Peroxydicarbonate Initiator req./10O g. D'-(2- henox eth l) Dibenzyl w Test 1 p y y Initiator Grams MoleX10- Shock sensitivity Negative at 15 inches Positive at 7 inches. Rapid heat 1 Mild explosion at Mild explosion at i a oyl peroxide 0. 5500 13.81 94 0. 90 c. Dibenzyl peroxydicarbonate 0. 0770 2. 55 Pressure vessel test 1.5 mm 7.8 mm. Di-(2-phen0xyethy1) peroxydicarbonate 0.0685 1. 89 Trauzl 15.51111 18.5 n11.

2 Tests sensitivity of peroxide to initiation by sholck or impact. ifiiiiititi alh iffififiiiiiieiiiZ iiipfiiiiii under rapid EXAMPLE v heat and partial confinement. i l d b133??35 2&8?its:ifittiotttimttfiitlgitttiitiif. as, SPI exotherms of -P Y Y case, is a safer peroxydicarbonate than is dibenzyl peroxydicarbonate. peroxydicarbonate F EXAMPLE v 60 The unsaturated polyester resin employed in this exam- Vinyl chloride polymerization efiiciencies Of dibenzyl ple was a mixture of an unsaturated polyester and styrene peroxydicarbonate, dilauroyl peroxide and di-(2-phemonomer, noxyethyl) peroxydicarbonate at 50 C./ 8 hrs. The unsaturated polyester was an alkyd resin made by Dibenzyl peroxydicarbonate is being promoted as a estenfymg the followmg components: thermally stable peroxydicarbonate replacement for dilauroyl peroxide in vinyl chloride polymerizations ow- Component: Quantity, moles ing to its greater efiiciency than that of dilauroyl per- Maleic anhydride 1.0 oxide, a standard peroxide used commercially in vinyl Phthalic anhydride 1. chloride polymerizations. Vinyl chloride suspension po- Propylene glycol 2.2

9 To the resulting resin was added 0.013% by weight of hydroquinone inhibitor. The alkyd resin had an Acid No. of 45-50. Seven (7) parts by weight of the above polyester (alkyd resin) was diluted with three (3) parts by weight of monomeric styrene. The resulting unsaturated polyester resin had the following properties:

(a) Viscosity (Broolcfield No. 2 at 20 r.p.m.): 13.08 poise. (b) Specific gravity: 1.14.

Curing procedure Gelation and cure characteristics of di-(Z-phenoxyethyl)peroxydicarbonate in the unsaturated polyester resin described above were determined using the Standard SPI Exotherm Procedure for Running Exotherm Curves- Polyester Resin, published in the preprint of the 16th Annual Conference-Reinforced Plastics Division, Society of the Plastic Industry, Inc. (Februray 1961).

Using this procedure, di-(2-phenoxyethyl) peroxydicarbonate, the peroxide of this invention, was evaluated as a curing catalyst for the unsaturated polyester resin at 100 C. The level of catalyst employed was that which was equal in active oxygen to 1% by weight of dibenzoyl peroxide (a commercially available low temperature curing catalyst). The results are summarized below in Example VI Table.

EXAMPLE VI TABLE 100 SPI exotherms of di-(Z-phenoxyethyl) peroxydicarbonate Gel, Cure, Peak, Peroxide min. min. F. Bareol Di-(2-phenoxyethyl) peroxydicarbonate- 0. 3 1. 3 375 25-30 Dibenzoyl peroxide 1. 8 2. 7 425 These results show that di-(Z-phenoxyethyl) peroxydicarbonate has greater activity than dibenzoyl peroxide in curing the resin.

What is claimed is:

1. Di-(2-phenoxyethyl) peroxydicarbonate.

References Cited FOREIGN PATENTS 7/1970 Germany.

OTHER REFERENCES Chemical Abstracts, vol. 64, 5271b (1966).

LEWIS GOTTS, Primary Examiner D. G. RIVERS, Assistant Examiner US. Cl. X.R.

26077.5 UA, 88.7 D, 89.3, 89.5 A, 91.1 R, 92.3, 92.8 W, 94.2 R, 94.9 A, 861 

